Particle collector system for electrical propulsion system testing



Dec. 27, 1966 A. E. LENNERT PARTICLE COLLECTOR SYSTEM FOR ELECTRICAL PROPULSION SYSTEM TESTING 2 Sheets-Sheet 1 Filed June 8, 1964 y 7 m i 0 T a W m rw M WK 4 M w W W Dec. 27, 1966 A. E. LENNERT 3,293,910

PARTICLE COLLECTOR SYSTEM FOR ELECTRICAL PROPULSION SYSTEM TESTING Filed June 8, 1964 2 Sheets-Sheet 2 Fan ff 54/91 4) INVENTOR.

United States Patent 3,293,910 PARTICLE COLLECTOR SYSTEM FOR ELEC- TRICAL PROPULSION SYSTEM TESTING Andrew E. Lennert, 10001 Pickett Drive, Tullahoma, Tenn. 37201 Filed June 8, 1964, Ser. No. 373,427 2 Claims. (Cl. 73116) This invention relates to an apparatus for the continuous removal of the exhaust products from an electrical propulsion system so that a high vacuum may be maintained.

One object of the invention is to provide an apparatus to provide a more efficient recovery of expensive propellant materials used in electrical propulsion systems from a vacuum chamber.

Another object of the invention is to provide an apparatus for removing exhaust products from an electrical propulsion system from a vacuum chamber which will keep the particles from moving back into the main chamber.

These and other objects will be more fully understood from the following detailed description taken with the drawing, wherein:

FIG. 1 is a schematic cross-sectional view of a gettering pump according to one embodiment of the invention, and

FIG. 2 is a schematic cross-sectional view of a modification of the device of FIG. 1.

In the testing of electrical propulsion systems for use in a vacuum environment, it is sometimes necessary to exhaust the products from the propulsion system into a high vacuum chamber. Continuous removal of the exhaust products from the vacuum chamber is necessary so that the high vacuum required for operation may be maintained.

According to this invention a separate collector chamber is provided at the downstream end of main chamber and a focusing system is provided to direct the beam from the propulsion system under test, into the collector cham ber. The beam is deflected to impinge on a liquid gettering material within the collector chamber. The liquid getter is removed from the collector chamber, degassed and then returned to the inlet reservoir for the collector chamber.

Referring now to FIG. 1 of the drawing reference number refers to a vacuum chamber into which products from an electrical propulsion system shown schematically at 11 are discharged. The chamber is evacuated by means of a conventional pumping system shown schematically at 12. The beam of directed energetic particles 13 from the electrical propulsion system 11 is brought to a focus in passage 15 leading to chamber 17, by means of focusing means shown schematically at 19 and 20. Other focusing means than that shown may be used as for example magnetic focusing. A plate member 22 is located in the lower portion of chamber 17 displaced from the beam axis 14 at an angle to the wall 23. A sheet of liquid getter material 24 from reservoir 25 passes over the plate 22 and is discharged into sump 26. The beam 13 is deflected toward the plate 22 by means of electrostatic deflection plates 29. Magnetic deflection means could also be used for some applications or a combination of magnetic and electrostatic deflection means could be used. Baifles 27 and 28 are provided to keep sputtered particles from migrating back into the chamber 10. A spool piece 31 is secured to chamber 17 and is used to seal the chamber 17 to an annular projection 32 on chamber 10. A standard gate valve shown schematically at 33 permits the isolation of chamber 17 from chamber 10 when desired. The liquid gettering material from sump 26 is fed to a standard degassing chamber 35 through a pump 36. The sorbed gases are removed in the degassing chamber 35 and returned to Patented Dec. 27, 1966 ICC supply chamber 37. The desorbed liquid gettering material is returned to the reservoir 25 through a pump 40 and a cooling system 41. The liquid gettering material is a low vapor pressure material which may be selected from the partial list of suitable materials given below,

Metal alloy: Weight percent Rubidium 14 Cesium 86 Sodium 4 Cesium 96 Potassium 24 Cesium 76 Cesium 73 Potassium 24 Sodium 3 Bismuth 1 Mercury 99 Cesium 2 Mercury 98 Mercury 99.9 Sodium 0.1

Also other gettering materials such as special oils may be used.

In the operation of the device after the electrical engine 11 under test is secured to the main chamber 10 the main chamber is evacuated by means of pump 12 to approximately 10 mm. Hg. The collector chamber is also pumped to a low pressure by means of pump 18. Power supply 45 is turned on to supply the focusing voltages to focusing electrodes 19 and 20 and deflection voltages to deflector plates 29. Pumps 36 and 40 are then started to supply a liquid flow across plate 22 and to recycle the liquid from sump 26. The test engine 11 is then started and directs a beam 13 through chamber 10. Some divergence of beam 13 takes place in the travel through chamber 10. The focusing system 19 and 20 focuses the beam so that it penetrates the passages 15 into chamber 17. As the beam enters the chamber 17 it is bent downwardly by deflection means 29 to impinge on the gettering material 24 on plate 22 by the liquid gettering material flow across plate 22 into sump 26. The liquid getter and sorbed gases are pumped from sump 26 into the degassing chamber 10 where the sorbed gases are removed and returned to supply chamber 37 by any standard method known in the art; for example, as described in the Batzer Patent 3,050,236. The desorbed gettering material is then returned to reservoir 26 through pump 40 and cooling system 41.

Since some of the gas particles acquire a greater charge than other particles they will be bent a greater amount by deflection means 29. About percent of the charged particles will hit the upper portion of plate 7 in the device of FIG. 1. A modification of the device of FIG. 1 is shown in FIG. 2 wherein like elements are given like reference numbers. With the device of FIG. 2 the major portion of the charged particles are made to impinge upon the liquid getter adjacent the sump. In this device all of the structure is the same as in FIG. 1 except that the plate 22' and getter reservoir 25' are located on the side of chamber 17' adjacent chamber 10. The deflection voltage is also increased to direct the beam toward plate 22'.

In some applications it is necessary to cool the chamber 17 and baffle plates 27 and 28. This may be accomplished with standard cooling tubes and a coolant such as Freon or any other standard cooling means.

There is thus provided an apparatus for providing continuous removal of the exhaust products from a high vacu- 11m chamber used to test an electrical propulsion system.

While certain specific embodiments have been described many changes may be made without departing from the general principles and scope of the invention.

I claim:

1. In combination with a vacuum test chamber adapted to have a test engine directing a stream of charged particles into said vacuum test chamber, a device for continuously removing exhaust products from said test chamber comprising: a collector chamber attached to said test chamber at the downstream end thereof and connected to said test chamber by a passage; means for focusing said charged particles through said passage into said collector chamber; a plate member within said collector chamber, displaced from the axis of said passage; means for providing a flow of liquid getter material across said plate member; means for deflecting said exhaust products toward said getter material; means within said collector chamber adjacent said passage for impeding the migration of sputtered particles into said test chamber; means for removing said getter material with the absorbed particles from said collector chamber; means for degassing said getter material and means for returning said gettering material to said plate member in said collector chamber.

2. In combination with a vacuum test chamber adapted to have a test engine directing a stream of charged particles along a predetermined path into said vacuum test chamher, a device for continuously removing exhaust products from said test chamber comprising: a collector chamber attached to said test chamber at the dOVWlStI'GHIH end thereof and connected to said test chamber by a passage; means for focusing said charged particles along said predetermined path through said passage into said collector chamber; a plate member withinsaid collector chamber, displaced from the axis of said stream of charged particles; said plate member having its upper end adjacent the wall of said collector chamber on the side of said passage and having its lower end projecting away from said wall of said collector chamber; means for providing a flow of liquid getter material across said plate member; means at the lower end of said plate member for collecting said getter material; means for deflecting said exhaust products toward said plate member and said getter material; means within said collector chamber adjacent said passage for impeding the migration of sputtered particles into said test chamber; means connected to said collecting means for removing said getter material with the absorbed particles from said collector chamber; means for degassing said getter material; means for cooling the degassed getter material and means for returning said getter material to said plate member in said collector chamber.

References Cited by the Examiner UNITED STATES PATENTS 2,763,125 9/1956 Kadosch et al 31380 X 3,050,236 8/1962 Batzer 230-69 3,199,343 8/1965 Childs et a1 731l6 RICHARD C. QUEISSER, Primary Examiner.

J. W. MYRACLE, Assistant Examiner. 

1. IN COMBINATION WITH A VACUUM TEST CHAMBER ADAPTED TO HAVE A TEST ENGINE DIRECTING A STREAM OF CHARGED PARTICLES INTO SAID VACUUM TEST CHAMBER, A DEVICE FOR CONTINUOUSLY REMOVING EXHAUST PRODUCTS FROM SAID TEST CHAMBER COMPRISING: A COLLECTOR CHAMBER ATTACHED TO SAID TEST CHAMBER AT THE DOWNSTREAM END THEREOF AND CONNECTED TO SAID TEST CHAMBER BY A PASSAGE; MEANS FOR FOCUSING SAID CHARGED PARTICLES THROUGH SAID PASSAGE INTO SAID COLLECTOR CHAMBER; A PLATE MEMBER WITHIN SAID COLLECTOR CHAMBER, DISPLACED FROM THE AXIS OF SAID PASSAGE; MEANS FOR PROVIDING A FLOW OF LIQUID GETTER MATERIAL ACROSS SAID PLATE MEMBER; MEANS FOR DEFLECTING SAID EXHAUST PRODUCTS TOWARD SAID GETTER MATERIAL; MEANS WITHIN SAID COLLECTOR CHAMBER ADJACENT SAID PASSAGE FOR IMPEDING THE MIGRATION OF SPUTTERED PARTICLES INTO SAID TEST CHAMBER; MEANS FOR REMOVING SAID GETTER MATERIAL WITH THE ABSORBED PARTICLES FROM SAID COLLECTOR CHAMBER; MEANS FOR DEGASSING SAID GETTER MATERIAL AND MEANS FOR RETURNING SAID GETTERING MATERIAL TO SAID PLATE MEMBER IN SAID COLLECTOR CHAMBER. 